If they detect it's a robo-caller, maybe from amateur moves like dialing sequential numbers or on the phone 24/7, they could then blacklist that number or even the whole area code if it was international. Make the country's diplomats promise to combat robo-calling in their own country to get the area code cleared.

If that makes sense to anyone else and has miraculously not been submitted, feel free to steal it.

We can't block based on caller-id, it's transmitted in-band which can be spoofed.

The out of band info, on the other hand, can identify where the call was framed up, which route it took to ring your phone, and what the actual phone number being used is. With this, I can block anything.

In order to do anything about robocalling, we need a new shift in providers ability to supply info. Or we have to setup PBXes for everyone at home with straight PRIs.